Baccelli, F, Machiraju, S, Veitch, D & Bolot, J 2011, 'Probing for Loss: The Case Against Probe Trains', IEEE Communications Letters, vol. 15, no. 5, pp. 590-592.
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Barua, B, Abolhasan, M & Safaei, F 2011, 'On the Symbol Error Probability of Multihop Parallel Relay Networks', IEEE COMMUNICATIONS LETTERS, vol. 15, no. 7, pp. 719-721.
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In this paper we analyze the symbol error probability (SEP) of a cooperative multihop parallel relay network in Rayleigh fading channels for M-ary Phase-shift keying (M-PSK) modulation. The general closed form expression of the SEP is derived. We present numerical results on the performance of the network.
Barua, B, Abolhasan, M, Safaei, F & Franklin, DR 2011, 'On the Error Exponent of Amplify and Forward Relay Networks', IEEE COMMUNICATIONS LETTERS, vol. 15, no. 10, pp. 1047-1049.
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In this letter we derive the exact random coding error exponent of a dual hop amplify and forward (AF) relay network with channel state information (CSI) assisted ideal relay gain. Numerical results have been presented, which provide insight about the performance tradeoff between the error exponent and the data rate of the network. Finally we present the capacity analysis of this relay network.
Chaczko, Z & Resconi, G 2011, 'Reasoning by SVD and Morphotronic Network', International Journal of Electronics and Telecommunications, vol. 57, no. 2, pp. 145-152.
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The immune system of the vertebrates possess the capabilities of 'intelligent' information processing, which include memory, the ability to learn, to recognize, and to make decisions with respect to unknown situations. The mathematical formalization of t
Chiu, C & Chaczko, Z 2011, 'Deployment of an Agent-based SANET Architecture for Healthcare Services', International Journal of Electronics and Telecommunications, vol. 57, no. 3, pp. 309-315.
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Deployment of an Agent-based SANET Architecture for Healthcare ServicesThis paper describes the adaptation of a computational technique utilizing Extended Kohonen Maps (EKMs) and Rao-Blackwell-Kolmogorov (R-B) Filtering mechanisms for the administration of Sensor-Actuator networks (SANETs). Inspired by the BDI (Belief-Desire-Intention) Agent model from Rao and Georgeff, EKMs perform the quantitative analysis of an algorithmic artificial neural network process by using an indirect-mapping EKM to self-organize, while the Rao-Blackwell filtering mechanism reduces the external noise and interference in the problem set introduced through the self-organization process. Initial results demonstrate that a combinatorial approach to optimization with EKMs and Rao-Blackwell filtering provides an improvement in event trajectory approximation in comparison to standalone cooperative EKM processes to allow responsive event detection and optimization in patient healthcare.
Cunha, I, Teixeira, R, Veitch, D & Diot, C 2011, 'Predicting and tracking internet path changes', ACM SIGCOMM Computer Communication Review, vol. 41, no. 4, pp. 122-133.
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This paper investigates to what extent it is possible to use traceroute-style probing for accurately tracking Internet path changes. When the number of paths is large, the usual traceroute based approach misses many path changes because it probes all paths equally. Based on empirical observations, we argue that monitors can optimize probing according to the likelihood of path changes. We design a simple predictor of path changes using a nearest neighbor model. Although predicting path changes is not very accurate, we show that it can be used to improve probe targeting. Our path tracking method, called DTrack, detects up to two times more path changes than traditional probing, with lower detection delay, as well as providing complete load-balancer information.
Du, C, Yang, J, Wu, Q & He, X 2011, 'Locating facial landmarks by support vector machine-based active shape model', International Journal of Intelligent Systems Technologies and Applications, vol. 10, no. 2, pp. 151-151.
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Active shape model (ASM) plays an important role in face research such as face recognition, pose estimation and gaze estimation. A crucial step of the common ASM is finding a new position for each facial landmark at each iteration. Mahalanobis distance minimisation is used for this finding, provided there are enough training data such that the grey-level profiles for each landmark following a multivariate Gaussian distribution. However, this condition could not be satisfied in most cases. In this paper, a novel method support vector machine-based active shape model (SVMBASM) is proposed for this task. It approaches the finding task as a small sample size classification problem. Moreover, considering the poor classification performance caused by the imbalanced dataset which contains more negative instances (incorrect candidates for new position) than positive instances (correct candidates for new position), a multi-class classification framework is further proposed. Performance evaluation on Shanghai Jiao Tong University face database shows that the proposed SVMBASM outperforms the original ASM in terms of the average error and average frequency of convergence. © 2011 Inderscience Enterprises Ltd.
Dyadyuk, V, Huang, X, Stokes, L & Pathikulangara, J 2011, 'Implementation of wideband digital beam forming in the E-band', International Journal of Microwave and Wireless Technologies, vol. 3, no. 3, pp. 259-266.
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This paper reports the test results of a small-scale prototype that implements a digitally beam-formed phased antenna array in the E-band. A four-channel dual-conversion receive RF module for 71–76 GHz frequency band has been developed and integrated with a linear end-fire antenna array. Wideband frequency-domain angle-of-arrival estimation and beam-forming algorithms were developed and implemented using Orthogonal Frequency Division Multiplexing (OFDM) with Quadrature Phase-Shift Keying (QPSK) at 1 Gbps. Measured performance is very close to the simulated results and experimental data for an analogue-beam-formed array. This work is a stepping stone toward practical realization of larger hybrid arrays in the E-band.
Gao, L, Xu, M, Yan, SF, Liu, MG, Hou, CH & Wang, DH 2011, 'Content-aware broadcast soccer video retargeting using fuzzy logic', Electronics Letters, vol. 47, no. 12, pp. 694-694.
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A content-aware video retargeting method is proposed for playing broadcast soccer video in small displays. Four visual perception clues are predefined based on soccer game-specific knowledge and modelled by visual attention features firstly. Then, a fuzzy logic inference system is proposed to estimate visual attention values (AVs) of ball and players by fusing attention features. AVs are later used to determine the region of interest (ROI) of each frame. Finally, a retargeted video is generated by the ROI of each frame with polynomial curve fitting for temporal smoothing. Both subjective and objective evaluation results are promising. © 2011 The Institution of Engineering and Technology.
Garcia-Vigueras, M, Gomez-Tornero, JL, Goussetis, G, Weily, AR & Guo, YJ 2011, '1D-Leaky Wave Antenna Employing Parallel-Plate Waveguide Loaded With PRS and HIS', IEEE Transactions on Antennas and Propagation, vol. 59, no. 10, pp. 3687-3694.
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A new type of one-dimensional leaky-wave antenna (LWA) with independent control of the beam-pointing angle and beamwidth is presented. The antenna is based on a simple structure composed of a bulk parallel-plate waveguide (PPW) loaded with two printed circuit boards (PCBs), each one consisting of an array of printed dipoles. One PCB acts as a partially reflective surface (PRS), and the other grounded PCB behaves as a high impedance surface (HIS). It is shown that an independent control of the leaky-mode phase and leakage rate can be achieved by changing the lengths of the PRS and HIS dipoles, thus resulting in a flexible adjustment of the LWA pointing direction and directivity. The leaky-mode dispersion curves are obtained with a simple Transverse Equivalent Network (TEN), and they are validated with three-dimensional full-wave simulations. Experimental results on fabricated prototypes operating at 15 GHz are reported, demonstrating the versatile and independent control of the LWA performance by changing the PRS and HIS parameters. © 2011 IEEE.
Garcia-Vigueras, M, Gomez-Tornero, JL, Goussetis, G, Weily, AR & Guo, YJ 2011, 'Enhancing Frequency-Scanning Response of Leaky-Wave Antennas Using High-Impedance Surfaces', IEEE Antennas and Wireless Propagation Letters, vol. 10, pp. 7-10.
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The use of high-impedance surfaces (HISs) to increase the frequency-scanning sensitivity of hollow leaky-wave antennas (LWAs) is presented. The LWA consists of a hollow rectangular waveguide with one of its narrow walls replaced by a partially reflective surface, and it is loaded with a metallodielectric HIS to increase its beam-scanning response. Theoretical results based on a simple transverse equivalent network illustrate the physical mechanism responsible for the improvement, and they are verified by experiments on a prototype working in the 11-16 GHz band. © 2006 IEEE.
Ge, Y, Esselle, KP & Bird, TS 2011, 'Compact Dielectric Resonator Antennas With Ultrawide 60%–110% Bandwidth', IEEE Transactions on Antennas and Propagation, vol. 59, no. 9, pp. 3445-3448.
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Ge, Y, Esselle, KP & Bird, TS 2011, 'Experimental demonstration of a dual‐band electromagnetic band‐gap resonator antenna made out of a simple, single‐layer frequency selective surface', Microwave and Optical Technology Letters, vol. 53, no. 8, pp. 1867-1869.
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AbstractThe new concept for realizing a dual‐band electromagnetic band‐gap (EBG) resonator antenna using a simple, single‐sided frequency selective surface (FSS) is demonstrated experimentally.The reversal of the gradient of the FSS reflection coefficient phase response, around a FSS resonance frequency, is exploited to achieve two cavity resonance bands in which the FSS behaves as a partially reflective surface (PRS) with an appropriate reflection phase. An FSS, with rectangular slots printed on one surface, is considered for demonstration. The measured performance of a prototype antenna in two bands, around 11.4 GHz and 13.4 GHz, is presented. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26112
Gomez-Tornero, JL, Quesada-Pereira, F, Alvarez-Melcon, A, Goussetis, G, Weily, AR & Guo, YJ 2011, 'Frequency Steerable Two Dimensional Focusing Using Rectilinear Leaky-Wave Lenses', IEEE Transactions on Antennas and Propagation, vol. 59, no. 2, pp. 407-415.
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The concept of frequency steerable two-dimensional electromagnetic focusing by using a tapered leaky-wave line source embedded in a parallel-plate medium is presented. Accurate expressions for analyzing the focusing pattern of a rectilinear leaky-wave lens (LWL) from its constituent leaky-mode tapered propagation constant are described. The influence of the main LWL structural parameters on the synthesis of the focusing pattern is discussed. The ability to generate frequency steerable focusing patterns has been demonstrated by means of an example involving a LWL in hybrid waveguide printed-circuit technology and the results are validated by a commercial full-wave solver. © 2010 IEEE.
Gomez-Tornero, JL, Weily, AR & Guo, YJ 2011, 'Rectilinear Leaky-Wave Antennas With Broad Beam Patterns Using Hybrid Printed-Circuit Waveguides', IEEE Transactions on Antennas and Propagation, vol. 59, no. 11, pp. 3999-4007.
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A theoretical study on the design of broadbeam leaky-wave antennas (LWAs) of uniform type and rectilinear geometry is presented. A new broadbeam LWA structure based on the hybrid printed-circuit waveguide is proposed, which allows for the necessary flexible and independent control of the leaky-wave phase and leakage constants. The study shows that both the real and virtual focus LWAs can be synthesized in a simple manner by tapering the printed-slot along the LWA properly, but the real focus LWA is preferred in practice. Practical issues concerning the tapering of these LWA are investigated, including the tuning of the radiation pattern asymmetry level and beamwidth, the control of the ripple level inside the broad radiated main beam, and the frequency response of the broadbeam LWA. The paper provides new insight and guidance for the design of this type of LWAs. © 2011 IEEE.
Jamdagni, A, Tan, T, Nanda, P, He, S & Liu, R 2011, 'Mahalanobis Distance Map Approach for Anomaly Detection of Web-Based Attacks', Journal of Network Forensics, vol. 2, no. 2, pp. 25-39.
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Web serverss and web-based applications are commonly used attack targets. The main issue are how to prevent unauthorized access and to protect web server from the attack. Intrusion Detection Systems and networks. This paper focuses on the detection of various web-based attacks using Geometrical Structure Anomaly Detectin (GSAD) model. Further, a novel algorithm is proposed using Linear Discriminant Analysis (LDA) for the selection of most discriminating features to reduce the computational complexity of payload-based GSAD model. GSAD model is based on a pattern recognition technique used in image payload features to calculate the difference between normal and abnormal network traffice. GSAD model is evaluated experimentally on the real attacks (GATECH) dataset and on the DARPA 1999 dataset.
Jiang, Y, He, X, Lin, F & Jia, W 2011, 'An Encoding and Labeling Scheme Based on Continued Fraction for Dynamic XML', Journal of Software, vol. 6, no. 10, pp. 2043-2049.
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Much research about labeling schemes has been conducted to efficiently determine the ancestor-descendant relationships and the document-order between any two random XML nodes without re-labeling for updates. In this paper, we present an efficient XML encoding and labeling scheme for dynamic XML document, named Continued Fraction-based Encoding (CFE). The proposed CFE scheme labels nodes with continued fractions and has the following three important properties: (1) CFE codes can be inserted between any two consecutive CFE codes with the orders kept and without re-encoding the existing nodes; (2) CFE is orthogonal to specific labeling schemes, thus it can be applied broadly to different labeling schemes or other applications to efficiently process the updates; (3) CFE supports all structural relationships query in XPath. Two test data sets were built for evaluation. The experimental results show that CFE provides fairly reasonable XML query processing performance while completely avoiding relabeling for updates. © 2011 ACADEMY PUBLISHER.
Liu, M, Guo, X, Zhou, A, Wang, S, Li, Z & Dutkiewicz, E 2011, 'Low latency IP mobility management: protocol and analysis', EURASIP Journal on Wireless Communications and Networking, vol. 2011, no. 1.
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Ma, M, Huang, X, Jiao, B & Guo, YJ 2011, 'Optimal Orthogonal Precoding for Power Leakage Suppression in DFT-Based Systems', IEEE Transactions on Communications, vol. 59, no. 3, pp. 844-853.
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A solution to the power leakage minimization problem in discrete Fourier transform (DFT) based communication systems is presented. In a conventional DFT based system, modulated subcarriers exhibit high sidelobe levels, which leads to significant out-of-band power leakage. Existing techniques found in the literature either do not achieve sufficient sidelobe suppression or suffer from significant spectral efficiency loss. Precoding can be seen as a general linear processing method for power leakage reduction, however, how to design the optimal linear precoder is still an open problem. In this paper, the power leakage suppression is first treated as a matrix Frobenius norm minimization problem, and then the optimal orthogonal precoding matrix design for the power leakage suppression is proposed based on singular value decomposition (SVD). By further exploiting the extra degrees of freedom in the precoding matrix, two kinds of optimized precoding matrices, one with multi-carrier property and the other with single-carrier property, are developed to take the advantages of orthogonal frequency division multiplexing (OFDM) and single carrier frequency division multiple access (SC-FDMA), respectively. Simulation results show that both the multi-carrier and the single-carrier precoding schemes achieve significant power leakage suppression, and have similar peak-to-average power ratio (PAPR) and bit-error-rate (BER) to those of OFDM and SC-FDMA systems, respectively. © 2011 IEEE.
Movassaghi, S, Abolhasan, M & Lipman, J 2011, 'Addressing Schemes for Body Area Networks', IEEE COMMUNICATIONS LETTERS, vol. 15, no. 12, pp. 1310-1313.
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This letter explores address allocation in Body Area Networks (BANs) and proposes two novel schemes - Optimized Prophet Address Allocation (OPAA) and Hierarchical Collision-free Address Protocol (HCAP). The aim of the schemes is to use fewer bits in the address space, solve address wastage problems, reduce collisions and improve power efficiency. The usability and efficiency of the proposed schemes is shown through simulation and analysis. © 2006 IEEE.
Otoom, AF, Gunes, H, Concha, OP & Piccardi, M 2011, 'MLiT: mixtures of Gaussians under linear transformations', PATTERN ANALYSIS AND APPLICATIONS, vol. 14, no. 2, pp. 193-205.
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The curse of dimensionality hinders the effectiveness of density estimation in high dimensional spaces. Many techniques have been proposed in the past to discover embedded, locally linear manifolds of lower dimensionality, including the mixture of principal component analyzers, the mixture of probabilistic principal component analyzers and the mixture of factor analyzers. In this paper, we propose a novel mixture model for reducing dimensionality based on a linear transformation which is not restricted to be orthogonal nor aligned along the principal directions. For experimental validation, we have used the proposed model for classification of five 'hard' data sets and compared its accuracy with that of other popular classifiers. The performance of the proposed method has outperformed that of the mixture of probabilistic principal component analyzers on four out of the five compared data sets with improvements ranging from 0. 5 to 3.2%. Moreover, on all data sets, the accuracy achieved by the proposed method outperformed that of the Gaussian mixture model with improvements ranging from 0.2 to 3.4%. © 2011 Springer-Verlag London Limited.
Paisitkriangkrai, S, Mei, T, Zhang, J & Hua, X-S 2011, 'Clip-based hierarchical representation for near-duplicate video detection', International Journal of Computer Mathematics, vol. 88, no. 18, pp. 3817-3833.
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Qin, P-Y, Guo, YJ, Cai, Y, Dutkiewicz, E & Liang, C-H 2011, 'A Reconfigurable Antenna With Frequency and Polarization Agility', IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, vol. 10, pp. 1373-1376.
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A new antenna with both frequency and polarization reconfigurability is presented. The antenna consists of a square microstrip patch with a single probe feed located along the diagonal line. The center of each edge of the patch is connected to a shorting post via a p-i-n diode for polarization switching and two varactor diodes for frequency tuning. By switching between the different states of the p-i-n diodes, the proposed antenna can produce radiation patterns with horizontal, vertical, or 45° linear polarization. By varying the dc bias voltage, the operating frequency of each polarization of the antenna can be independently tuned. The frequency tuning range is from 1.35 to 2.25 GHz (|S11| <; -10 dB) for either horizontal or vertical polarization and from 1.35 to 1.9 GHz for the 45° linear polarization. Measured results on frequency tuning ranges and radiation patterns agree well with numerical simulations.
Sabbagh, AA, Braun, R & Abolhasan, M 2011, 'A comprehensive survey on rat selection algorithms for heterogeneous networks', World Academy of Science, Engineering and Technology, vol. 73, pp. 141-145.
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Due to the coexistence of different Radio Access Technologies (RATs), Next Generation Wireless Networks (NGWN) are predicted to be heterogeneous in nature. The coexistence of different RATs requires a need for Common Radio Resource Management (CRRM) to support the provision of Quality of Service (QoS) and the efficient utilization of radio resources. RAT selection algorithms are part of the CRRM algorithms. Simply, their role is to verify if an incoming call will be suitable to fit into a heterogeneous wireless network, and to decide which of the available RATs is most suitable to fit the need of the incoming call and admit it. Guaranteeing the requirements of QoS for all accepted calls and at the same time being able to provide the most efficient utilization of the available radio resources is the goal of RAT selection algorithm. The normal call admission control algorithms are designed for homogeneous wireless networks and they do not provide a solution to fit a heterogeneous wireless network which represents the NGWN. Therefore, there is a need to develop RAT selection algorithm for heterogeneous wireless network. In this paper, we propose an approach for RAT selection which includes receiving different criteria, assessing and making decisions, then selecting the most suitable RAT for incoming calls. A comprehensive survey of different RAT selection algorithms for a heterogeneous wireless network is studied.
Sun, Y, Zhang, Y, Song, Y & Dutkiewicz, E 2011, 'Fast RSVP: Efficient RSVP Mobility Support for Mobile IPv6', Wireless Personal Communications, vol. 60, no. 4, pp. 769-807.
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Tune, P & Veitch, D 2011, 'Fisher Information in Flow Size Distribution Estimation', IEEE Transactions on Information Theory, vol. 57, no. 10, pp. 7011-7035.
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Xiaojing Huang & Guo, YJ 2011, 'Frequency-Domain AoA Estimation and Beamforming with Wideband Hybrid Arrays', IEEE Transactions on Wireless Communications, vol. 10, no. 8, pp. 2543-2553.
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High speed long range millimetre-wave (mm-wave) links can be achieved by using wideband hybrid antenna arrays of sub-arrays. Due to the array architecture difference, conventional wideband angle-of-arrival (AoA) estimation and beamforming techniques are not applicable to such wideband hybrid arrays. Targeted at point-to-point line-of-sight wireless transmission in the 70/80 GHz E bands, a unified frequency-domain AoA estimation and beamforming algorithm suitable for large scale wideband hybrid arrays of both interleaved and side-by-side sub-arrays is proposed in this paper. The AoA estimation performance is analyzed by deriving a recursive modified Cramr-Rao bound (MCRB). The effect of mutual coupling among antenna elements on the estimation performance is also considered for the hybrid array of side-by-side sub-arrays. The analytical results can be used to determine system parameters according to required system specifications. Simulation results show that the proposed AoA estimation algorithm is robust against practical impairments, and the frequency dependency of the array pattern is significantly reduced after digital beamforming. Simulated mean square errors of AoA estimation are also compared with the analytical bounds, showing that the derived recursive MCRB provides a meaningful indication to the AoA estimation performance. © 2006 IEEE.
Yong Cai & Guo, YJ 2011, 'A Frequency-Agile Compact Array With a Reconfigurable Decoupling and Matching Network', IEEE Antennas and Wireless Propagation Letters, vol. 10, pp. 1031-1034.
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A new frequency-agile compact antenna array incorporating a reconfigurable decoupling and matching network (DMN) is presented. The array consists of two printed monopole antennas, each loaded with a p-i-n diode. By changing the p-i-n diode states through an inductive biasing line, the array operating frequency can be tuned to the 2.5-or 3.5-GHz band. The array interelement spacing is chosen to be as small as 0.05 λ 0 at 2.5 GHz, which results in a strong mutual coupling between antenna ports. A reconfigurable DMN is proposed to reduce the mutual coupling when the array frequency is switched. Measured results show that the use of the DMN realizes a matched (S 11 ≤-10 dB) and decoupled (S 21 ≤-20 dB) bandwidth of 150 and 160 MHz in the lower and higher bands, respectively. In addition, compared to the strongly coupled array, at least 9% antenna total efficiency improvement is measured over a 125-MHz bandwidth in both the lower and the higher bands. The effect of the ohmic loss in the DMN on the antenna correlation is also investigated. © 2011 IEEE.
Zheng, L, He, X, Wu, Q & Samali, B 2011, 'A system for licence plate recognition using a hierarchically combined classifier', International Journal of Intelligent Systems Technologies and Applications, vol. 10, no. 2, pp. 189-189.
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In a real time, automatic licence plate recognition system, licence detection, character segmentation and character recognition are three important components. All these three components generally require high accuracy and fast recognition speed to process. In this paper, general processing steps for license plate recognition (LPR) are addressed. After three types of combined classifiers are introduced and compared, a hierarchically combined classifier is designed based on an inductive learning-based method and an support vector machine (SVM)-based classification. This approach employs the inductive learning-based method to roughly divide all classes into smaller groups. Then, the SVM approach is used for character classification in individual groups. Having obtained a collection of samples of characters in advance from licence plates after licence detection and character segmentation steps, some known samples are available for training. After the training process, the inductive learning rules are extracted for rough classification and the parameters used for SVM-based classification are obtained. Then, a classification tree is constructed for next fast training and testing processes based on SVMs. The experimental results show that the hierarchically combined classifier is better than either the inductive learning-based classification or the SVM-based classification with a lower error rate and a faster processing speed. © 2011 Inderscience Enterprises Ltd.
Ahmad, MR, Rashid, M, Aziz, MHA, Esa, MM, Cooray, V, Rahman, M & Dutkiewicz, E 1970, 'Analysis of lightning-induced transient in 2.4 GHz wireless communication system', Proceeding of the 2011 IEEE International Conference on Space Science and Communication (IconSpace), 2011 International Conference on Space Science and Communication (IconSpace), IEEE, Penang, Malaysia, pp. 225-230.
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This paper analyzes the effects of transient from lightning channel to wireless communication system operating in microwave band at 2.4 GHz. Received Signal Strength Indicator (RSSI) measurement method has been used to capture 3 lightning flashes (naked eyes method) with 7 spikes recorded at r distance from the lightning channel base with fixed d Transmitter-Receiver (T-R) separation at 1 meter. The transient effects have been evaluated in terms of Electric Field Strength, Signal-to-Interference-Noise Ratio (SINR), Bit Error Rate (BER) and Packet Error Rate (PER). During the first lightning flash event, more than 50% of total transmitted packets were corrupted for at least 3 seconds duration. The same happens during the second and third lightning flash events with more than 40% and 15% packets corrupted for durations of 3 and 2 seconds respectively. Interestingly the most suffered traffic types are video and speech signal transmission while data transmission is not affected at all. © 2011 IEEE.
Al Sabbagh, A & Braun, RM 1970, 'A Markovian Model for Load-Balancing Based and Service Based Algorithms in B3G Networks', International Conference on Communications, Networking and Mobile Computing (ICCNMC 2011), International Conference on Networking and Mobile Computing, World Academy of Science, Engineering and Technology (WASET), Dubai, UAE, pp. 827-833.
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Next Generation Wireless Network (NGWN) is expected to be a heterogeneous network which integrates all different Radio Access Technologies (RATs) through a common platform. A major challenge is how to allocate users to the most suitable RAT for them. An optimized solution can lead to maximize the efficient use of radio resources, achieve better performance for service providers and provide Quality of Service (QoS) with low costs to users. Currently, Radio Resource Management (RRM) is implemented efficiently for the RAT that it was developed. However, it is not suitable for a heterogeneous network. Common RRM (CRRM) was proposed to manage radio resource utilization in the heterogeneous network. This paper presents a user level Markov model for a three co-located RAT networks. The load-balancing based and service based CRRM algorithms have been studied using the presented Markov model. A comparison for the performance of load-balancing based and service based CRRM algorithms is studied in terms of traffic distribution, new call blocking probability, vertical handover (VHO) call dropping probability and throughput.
Al Sabbagh, A, Braun, RM & Abolhasan, M 1970, 'A Comprehensive Survey on RAT Selection Algorithms for Beyond 3G Networks', International Conference on Communications, Networking and Mobile Computing (ICCNMC 2011), International Conference on Computer Networks and Mobile Computing, World Academy of Science, Engineering and Technology - WASET, Dubai, pp. 834-838.
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Due to the coexistence of different Radio Access Technologies (RATs), Next Generation Wireless Networks (NGWN) are predicted to be heterogeneous in nature. The coexistence of different RATs requires a need for Common Radio Resource Management (CRRM) to support the provision of Quality of Service (QoS) and the efficient utilization of radio resources. RAT selection algorithms are part of the CRRM algorithms. Simply, their role is to verify if an incoming call will be suitable to fit into a heterogeneous wireless network, and to decide which of the available RATs is most suitable to fit the need of the incoming call and admit it. Guaranteeing the requirements of QoS for all accepted calls and at the same time being able to provide the most efficient utilization of the available radio resources is the goal of RAT selection algorithm. The normal call admission control algorithms are designed for homogeneous wireless networks and they do not provide a solution to fit a heterogeneous wireless network which represents the NGWN. Therefore, there is a need to develop RAT selection algorithm for heterogeneous wireless network. In this paper, we propose an approach for RAT selection which includes receiving different criteria, assessing and making decisions, then selecting the most suitable RAT for incoming calls. A comprehensive survey of different RAT selection algorithms for a heterogeneous wireless network is studied.
Babar, A, Wong, B & Qumer, A 1970, 'An evaluation of the goal-oriented approaches for modelling strategic alignment concept.', RCIS, International Conference on Research Challenges in Information Science, IEEE, Gosier, pp. 1-8.
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Several frameworks have been proposed in Requirements Engineering (RE) discipline that use goal-oriented approach to model the concept of strategic alignment. Understanding the concept of strategic alignment from the perspective of Management Information Systems (MIS) discipline and evaluating goal-oriented approaches in the context of strategic alignment appear to be the fundamental weakness in the RE frameworks that claim to model strategic alignment. In this research we developed a list of constructs by analysing the concept of strategic alignment embedded in strategy map which is one of the widely used frameworks to develop strategic alignment in MIS discipline. In this regard we analysed details of a case study conducted to develop strategic alignment. Against the identified list of constructs we evaluated five well-known goal-oriented approaches and presented their level of effectiveness to model the concept of strategic alignment. © 2011 IEEE.
Borzeshi, EZ, Piccardi, M & Xu, RYD 1970, 'A discriminative prototype selection approach for graph embedding in human action recognition', 2011 IEEE International Conference on Computer Vision Workshops (ICCV Workshops), 2011 IEEE International Conference on Computer Vision Workshops (ICCV Workshops), IEEE, Barcelona Spain, pp. 1295-1301.
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This paper proposes a novel graph-based method for representing a human's shape during the performance of an action. Despite their strong representational power, graphs are computationally cumbersome for pattern analysis. One way of circumventing this problem is that of transforming the graphs into a vector space by means of graph embedding. Such an embedding can be conveniently obtained by way of a set of 'prototype' graphs and a dissimilarity measure: yet, the critical step in this approach is the selection of a suitable set of prototypes which can capture both the salient structure within each action class as well as the intra-class variation. This paper proposes a new discriminative approach for the selection of prototypes which maximizes a function of the inter- and intra-class distances. Experiments on an action recognition dataset reported in the paper show that such a discriminative approach outperforms well-established prototype selection methods such as center, border and random prototype selection.
Borzeshi, EZ, Xu, R & Piccardi, M 1970, 'Automatic Human Action Recognition in Videos by Graph Embedding', Lecture Notes in Computer Science.Image Analysis and Processing - ICIAP 2011.16th International Conference Part II, International Conference on Image Analysis and Processing, Springer Berlin Heidelberg, Ravenna, Italy, pp. 19-28.
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The problem of human action recognition has received increasing attention in recent years for its importance in many applications. Yet, the main limitation of current approaches is that they do not capture well the spatial relationships in the subject performing the action. This paper presents an initial study which uses graphs to represent the actorâs shape and graph embedding to then convert the graph into a suitable feature vector. In this way, we can benefit from the wide range of statistical classifiers while retaining the strong representational power of graphs. The paper shows that, although the proposed method does not yet achieve accuracy comparable to that of the best existing approaches, the embedded graphs are capable of describing the deformable human shape and its evolution along the time. This confirms the interesting rationale of the approach and its potential for future performance.
Borzeshi, EZ, Xu, R & Piccardi, M 1970, 'Automatic Human Action Recognition in Videos by Graph Embedding', IMAGE ANALYSIS AND PROCESSING - ICIAP 2011, PT II, 16th International Conference on Image Analysis and Processing (ICIAP), SPRINGER-VERLAG BERLIN, Ravenna, ITALY, pp. 19-28.
Cai, Y & Jay Guo, Y 1970, 'A reconfigurable decoupling and matching network for a frequency agile compact array', Proceedings of the 5th European Conference on Antennas and Propagation, EUCAP 2011, pp. 896-899.
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A novel frequency reconfigurable compact array incorporating a reconfigurable decoupling and matching network (DMN) is proposed. The array radiating part consists of two printed monopole antennas. An inductive biasing line is devised to control the PIN diode states so that the array operating frequency is switchable between 2.5 and 3.5 GHz bands. The element spacing is chosen to be as small as 0.050 at 2.5GHz, which leads to a strong mutual coupling between antenna ports. A reconfigurable DMN is proposed to mitigate the mutual coupling effect for both 2.5 and 3.5GHz bands. Simulation results show that the use of the DMN realizes a well matched (S11 <= -10dB) and decoupled (S21 <= -20dB) bandwidth of 70MHz and 120MHz in the lower and higher bands, respectively. The antenna total efficiency can be substantially affected by the internal resistor when the PIN diodes are in the ON state. The compact size and frequency reconfigurability feature greatly save the antenna real estate. The decoupled array can be useful for a multi-input multi-output (MIMO) diversity system. © 2011 EurAAP.
Chaczko, Z & Aslanzadeh, S 1970, 'C2EN: Anisotropic Model of Cloud Computing', 2011 21st International Conference on Systems Engineering, 2011 21st International Conference on Systems Engineering (ICSEng), IEEE, Las Vegas, Nevada, USA, pp. 467-473.
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In Cloud computing, due to non-locale and a multi-tenancy of services and resources, there is a need for sophisticated methods for the metering of efficiency, availability and utilisation of services and resources. Setup and management of computing infrastructure, that is in a state of constant flux, related uncertainties of the state of individual elements as well as levels of their usage per application or user on an hourly, daily, weekly, monthly, and yearly basis - pose serious challenges. This paper describes how the Anisotropic Network concept, with its mathematical apparatus, can be adopted to model, monitor and manage usage of the cloud computing resources and services seen as an elastic network of interacting elements that are in a constant motion. Various aspects of service utilisation prediction and anisotropic resource movements related to the novel Cloud Computing Elastic Network (C2EN) model will be discussed in the context of a mathematical model and experimental results of simulations.
Chaczko, Z, Aslanzadeh, S & Klempous, R 1970, 'Development of software with cloud computing in 3TZ collaborative team environment', 7th International Conference on Broadband Communications and Biomedical Applications, 2011 6th International Conference on Broadband and Biomedical Communications (IB2Com), IEEE, Melbourne, Australia, pp. 318-323.
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In the global economy, we have seen a decrease in the barriers towards communication across the globe along with an increase of service availability to support this communication. Software development is one discipline that is capable of effectively utilizing and benefiting from global collaboration prospect lent by ever increasing capability of information and communication technology. 24-hour continues development is ideal for application towards tasks that have hard-deadlines or require work completed as soon as possible. This article will mainly focus on introducing 24/7 global models that can be applied in cloud environment used in three different time zones. The case study related to developing agricultural software has been investigated in this article.
Chaczko, Z, Chiu, C, Aslanzadeh, S & Dune, T 1970, 'Software Infrastructure for Wireless Sensor and Actuator Networks.', ICSEng, International Conference on Systems Engineering, IEEE, Las Vegas, Nevada, USA, pp. 474-479.
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In the development of large ad-hoc Wireless Sensor and Actuator Agent Networks (SANETS), a multitude of disparate problems are faced. In order for these networks to function, software must be able to effectively manage: unreliable dynamic distributed communication, the power constraints of un-wired devices, failure of hardware devices in hostile environments and the remote allocation of distributed processing tasks throughout the network. The solutions to these problems must be solved in a highly scalable manner. The paper describes the process of analysis of the requirements and presents a design of a service-oriented software infrastructure (middleware) solution for scalable ad-hoc networks, in a context of a system made of mobile sensors and actuators.
Chan, KY & Guo, YJ 1970, 'Analysis of RF MEMS integrated tunable high impedance surface at 60 GHz', Asia-Pacific Microwave Conference Proceedings, APMC, Asia-Pacific Microwave Conference, IEEE, Melbourne, VIC, Australia, pp. 562-565.
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This paper presents an analysis of tunable high impedance surface (HIS) integrated with RF MEMS varactors at 60 GHz. The HIS phase response with different number of RF MEMS varactors integrated with dipoles is shown. The effect of shifting RF MEMS varactors across the proposed dipoles and patches are highlighted. This paper provides a guideline for designing HIS integrated with RF MEMS varactors. It illustrates the significance of RF MEMS varactor location versus HIS phase response. © 2011 Engineers Australia.
Chen, S, Nepal, S & Liu, R 1970, 'Secure Connectivity for Intra-cloud and Inter-cloud Communication', 2011 40th International Conference on Parallel Processing Workshops, 2011 International Conference on Parallel Processing Workshops (ICPPW), IEEE, Taipei City, Taiwan, pp. 154-159.
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The cloud has become an attractive platform for enterprises to deploy and execute their business services for B2B collaborations. Naturally, some of the confidential B2B collaborations require secure tunnels to secure the messaging between the services that are deployed within the same cloud or different clouds. This article examines this issue by reviewing existing network security technologies and presenting an electronic contract based solution that provides a secure Connectivity as a Service (CaaS) for intra-cloud and inter-cloud communications with little or no configuration effort. © 2011 IEEE.
Chen, X, He, X, Yang, J & Wu, Q 1970, 'An effective document image deblurring algorithm', CVPR 2011, 2011 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), IEEE, Colorado Springs, pp. 369-376.
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Deblurring camera-based document image is an important task in digital document processing, since it can improve both the accuracy of optical character recognition systems and the visual quality of document images. Traditional deblurring algorithms have been proposed to work for natural-scene images. However the natural-scene images are not consistent with document images. In this paper, the distinct characteristics of document images are investigated. We propose a content-aware prior for document image deblurring. It is based on document image foreground segmentation. Besides, an upper-bound constraint combined with total variation based method is proposed to suppress the rings in the deblurred image. Comparing with the traditional general purpose deblurring methods, the proposed deblurring algorithm can produce more pleasing results on document images. Encouraging experimental results demonstrate the efficacy of the proposed method. © 2011 IEEE.
Concha, OP, Da Xu, RY, Moghaddam, Z & Piccardi, M 1970, 'HMM-MIO: An enhanced hidden Markov model for action recognition', CVPR 2011 WORKSHOPS, 2011 IEEE Computer Society Conference on Computer Vision and Pattern Recognition Workshops (CVPR Workshops), IEEE, Colorado Spring, CO, pp. 62-69.
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Generative models can be flexibly employed in a variety of tasks such as classification, detection and segmentation thanks to their explicit modelling of likelihood functions. However, likelihood functions are hard to model accurately in many real cases. In this paper, we present an enhanced hidden Markov model capable of dealing with the noisy, high-dimensional and sparse measurements typical of action feature sets. The modified model, named hidden Markov model with multiple, independent observations (HMM-MIO), joins: a) robustness to observation outliers, b) dimensionality reduction, and c) processing of sparse observations. In the paper, a set of experimental results over the Weizmann and KTH datasets shows that this model can be tuned to achieve classification accuracy comparable to that of discriminative classifiers. While discriminative approaches remain the natural choice for classification tasks, our results prove that likelihoods, too, can be modelled to a high level of accuracy. In the near future, we plan extension of HMM-MIO along the lines of infinite Markov models and its integration into a switching model for continuous human action recognition. © 2011 IEEE.
Cunha, I, Teixeira, R, Veitch, D & Diot, C 1970, 'Predicting and tracking internet path changes', Proceedings of the ACM SIGCOMM 2011 conference, SIGCOMM '11: ACM SIGCOMM 2011 Conference, ACM, Toronto, Ontario, Canada, pp. 122-133.
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This paper investigates to what extent it is possible to use traceroute-style probing for accurately tracking Internet path changes. When the number of paths is large, the usual traceroute based approach misses many path changes because it probes all paths equally. Based on empirical observations, we argue that monitors can optimize probing according to the likelihood of path changes. We design a simple predictor of path changes using a nearest neighbor model. Although predicting path changes is not very accurate, we show that it can be used to improve probe targeting. Our path tracking method, called DTrack, detects up to two times more path changes than traditional probing, with lower detection delay, as well as providing complete load-balancer information.
Dong, YF, Kanhere, S, Chou, CT & Ren Ping Liu 1970, 'Automatic image capturing and processing for PetrolWatch', 2011 17th IEEE International Conference on Networks, 2011 17th IEEE International Conference on Networks (ICON), IEEE, Singapore, Singapore, pp. 236-240.
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In our previous work [1], we proposed a Participatory Sensing (PS) architecture called PetrolWatch to collect and share fuel prices from camera images of road-side price board (billboard) of service (or gas) stations. A key part of the PetrolWatch architecture, and the main focus of this paper, is the automatic billboard image capture from a moving car without user intervention. We develop the system design and implementation of the automatic image collection for PetrolWatch. Capturing a clear image by an unassisted mobile phone from a moving car is proved to be a challenge by our street driving experiments. We design the camera control and image pre-selection schemes to address this challenge. In particular, we leverage the advanced capabilities of modern mobile phones to design an acceptable camera triggering range and set the camera focus accordingly. Experiment results show that our design improve fuel price extraction rate by more than 40%. To deal with blurred images caused by vehicle vibrations, we design a set of pre-selection thresholds based on the measures from embedded accelerometer of the mobile phone. Our experiments show that our pre-selection improves the system efficiency by eliminating 78.57% of the blurred images. © 2011 IEEE.
Fang, G, Dutkiewicz, E, Huq, MA, Vesilo, R & Yang, Y 1970, 'Medical Body Area Networks: Opportunities, challenges and practices', 2011 11th International Symposium on Communications & Information Technologies (ISCIT), 2011 11th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Hangzhou, China, pp. 562-567.
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Medical Body Area Network (MBAN) is a new wireless communications technology designed to sense human's vital signals through tiny nodes in, on and around the human body wirelessly. MBAN will play an important role in enabling ubiquitous and non-invasive telemetry and healthcare systems in the future. In this paper, we firstly explore the opportunities of MBAN from the point of new applications, and then we analyze the enabling technologies and challenges to achieve the goal of MBAN, which includes energy efficiency, robustness, high data rate for video support and network co-existence issues. Finally, we describe our MQWIN400 radio platform which was designed to work at 400MHz MICS band, as well as the related research activities and experimental results. © 2011 IEEE.
Gill, AQ & Bunker, D 1970, 'Connceptualization of a Context Aware Cloud Adaptation (CACA) Framework', 2011 IEEE Ninth International Conference on Dependable, Autonomic and Secure Computing (DASC), International Conference on Dependable, Autonomic and Secure Computing, IEEE CPS, Sydney, pp. 760-767.
Gill, AQ, Bunker, D & Seltsikas, P 1970, 'An Empirical Analysis of Cloud, Mobile, Social and Green Computing: Financial Services IT Strategy and Enterprise Architecture.', DASC, International Conference on Dependable, Autonomic and Secure Computing, IEEE Computer Society, Sydney, pp. 697-704.
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Financial services organisations have shown a significant interest in the adoption of emerging cloud, mobile, social networks and green computing environments for managing the needs of their complex business processes and systems. How will these emerging technologies affect and be embraced by financial services organizations in practice? This paper presents empirical exploratory research on the applicability of emerging cloud, mobile, social and green technologies in these organizations. We investigate how these emerging technologies will affect the IT strategy and enterprise architecture of the financial services organisations by analyzing recent interviews of fifteen senior technology executives and CIOs from this sector. The outcomes of this study suggest that the sector perceives these emerging technologies both as a challenge and opportunity for their businesses. In order to meet their business objectives they do, however, require a phased, systematic, people-oriented, business-focused and low risk approach that combines both business and technology impacts to the assessment, selection, consolidation and adoption of these technologies for specific business services without putting their customers' information at risk. © 2011 IEEE.
He, Y, Wang, J, Su, Y, Dutkiewicz, E, Huang, X & Shi, J 1970, 'An efficient implementation of PRACH generator in LTE UE transmitters', 2011 7th International Wireless Communications and Mobile Computing Conference, 2011 7th International Wireless Communications and Mobile Computing Conference (IWCMC 2011), IEEE, Istanbul, Turkey, pp. 2226-2230.
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An efficient hardware-optimized Physical Random Access Channel (PRACH) baseband signal generation algorithm and its ASIC implementation in the LTE user equipment (UE) transmitter are presented in this paper. A simplified DFT of the Zadoff-Chu (ZC) sequence as well as a phase computation are applied to the prime size DFT of the PRACH preamble and the large size IDFT is accomplished by groups of smaller size IFFTs. The optimized algorithm achieves significantly lower computational complexity compared with the original algorithm in the LTE specification and better performance compared to another publication. The ASIC architecture is also designed to reduce the memory size and logic complexity, which achieves a low hardware cost in terms of the cell area. The proposed design was implemented in 65nm CMOS and it was demonstrated that this design can satisfy the timing requirements of the LTE specification. © 2011 IEEE.
Huang, X & Guo, YJ 1970, 'Closed-form MSE performance for phase estimation from Gaussian reference signals', 2011 11th International Symposium on Communications & Information Technologies (ISCIT), 2011 11th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Hangzhou, China, pp. 154-158.
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In many communications and signal processing applications, phase information carried on Gaussian distributed reference signals is often required for various purposes, such as the carrier frequency offset estimation in orthogonal frequency division multiplexing (OFDM) systems. The performance of phase estimation is usually measured by the mean square error (MSE) which is often infeasible to obtain. Instead, the Cramér-Rao Bound (CRB) and modified Cramér-Rao Bound (MCRB) are used to give lower MSE bounds for the phase estimation. This paper presents closed-form MSE approximations for estimating phase information from Gaussian reference signals, which provide better indications of the MSE performance than the MCRB. It is also shown that the MCRB is only attainable at high signal-to-noise ratios and with large number of observed signal samples. Simulated and analytical results are compared to demonstrate the accuracy and efficiency of the derived MSE formulas. © 2011 IEEE.
Kazemi, R, Vesilo, R & Dutkiewicz, E 1970, 'A Novel Genetic-Fuzzy Power Controller with Feedback for Interference Mitigation in Wireless Body Area Networks', 2011 IEEE 73rd Vehicular Technology Conference (VTC Spring), 2011 IEEE Vehicular Technology Conference (VTC 2011-Spring), IEEE, Yokohama, Japan.
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Wireless Body Area Networks (WBANs) are an emerging technology for short-range wireless communication inside, on or around the human body, mainly for medical applications. A WBAN's scarcest resource is power. Due to the mobility of WBANs as well as the limited number of available channels, signals of neighboring WBANs can cause interference that may severely degrade the reliability and performance of the system and lead to more power consumption. In this paper, we propose a fast converging fuzzy power controller (FPC) with feedback whose inputs are the current interference power level, Signal-to-Interference-and-Noise (SINR) and the current transmission power level to provide interference mitigation in WBANs. We utilize a genetic algorithm to design and optimize the FPC to simultaneously maximize capacity, minimize power consumption and minimize convergence time. We compare the performance of the proposed approach with two game-theory power control approaches. Our simulation results show that compared to these other approaches, the proposed FPC provides a substantial saving in power consumption as well as quick convergence that is independent of the number of nodes in the system, while sacrificing only a small amount of capacity. © 2011 IEEE.
Kazemi, R, Vesilo, R, Dutkiewicz, E & Ren Liu 1970, 'Dynamic power control in Wireless Body Area Networks using reinforcement learning with approximation', 2011 IEEE 22nd International Symposium on Personal, Indoor and Mobile Radio Communications, 2011 IEEE 22nd International Symposium on Personal, Indoor and Mobile Radio Communications - (PIMRC 2011), IEEE, Toronto, ON, Canada, pp. 2203-2208.
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A Wireless Body Area Network (WBAN) is made up of multiple tiny physiological sensors implanted in/on the human body with each sensor equipped with a wireless transceiver that communicates to a coordinator in a star topology. Energy is the scarcest resource in WBANs. Power control mechanisms to achieve a certain level of utility while using as little power for transmission as possible can play an important role in reducing energy consumption in such very energy-constrained networks. In this paper, we propose a novel power controller to mitigate internetwork interference in WBANs and increase the maximum achievable throughput with the minimum energy consumption. The proposed power controller employs reinforcement learning with approximation to learn from the environment and improve its performance. We compare the performance of the proposed controller to two other power controllers, one based on game theory and the other one based on fuzzy logic. Simulation results show that compared to the other two approaches, RLPC provides a substantial saving in energy consumption per bit, with a substantial increase in network lifetime. © 2011 IEEE.
Khan, MAY & Veitch, D 1970, 'SmartRate: A new dynamic rate adaptation algorithm for 802.11 wireless networks', 2011 IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks, 2011 IEEE International Symposium on 'A World of Wireless, Mobile and Multimedia Networks' (WoWMoM), IEEE, Lucca, Italy, pp. 1-10.
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Traditional rate adaptation algorithms (RAAs) suffer under congested scenarios as they are unable to differentiate between packet errors due to poor physical channel conditions, from those due to collisions arising from contention for the channel. This degrades the rate selection which results in a dramatic loss of throughput both for individual users and the system. This paper presents `SmartRate', a throughput and packet size aware, passive measurement based, clientside RAA. It employs 802.11 MAC fragmentation for physical PER isolation, and employs a dynamic sampling regime to collect per-rate statistics. It uses a novel RSSI based volatility adaptivity mechanism to fine tune various parameters of the algorithm under different channel conditions (stationary or mobile). We compare SmartRate against SampleRate and AMRR in our wireless testbed and show that SmartRate outperforms them in single and multi-user cases.
Kusakunniran, W, Wu, Q, Zhang, J & Li, H 1970, 'Pairwise Shape configuration-based PSA for gait recognition under small viewing angle change', 2011 8th IEEE International Conference on Advanced Video and Signal Based Surveillance (AVSS), 2011 8th IEEE International Conference on Advanced Video and Signal Based Surveillance (AVSS), IEEE, Klagenfurt, Austria, pp. 17-22.
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Two main components of Procrustes Shape Analysis (PSA) are adopted and adapted specifically to address gait recognition under small viewing angle change: 1) Procrustes Mean Shape (PMS) for gait signature description; 2) Procrustes Distance (PD) for similarity measurement. Pairwise Shape Configuration (PSC) is proposed as a shape descriptor in place of existing Centroid Shape Configuration (CSC) in conventional PSA. PSC can better tolerate shape change caused by viewing angle change than CSC. Small variation of viewing angle makes large impact only on global gait appearance. Without major impact on local spatio-temporal motion, PSC which effectively embeds local shape information can generate robust view-invariant gait feature. To enhance gait recognition performance, a novel boundary re-sampling process is proposed. It provides only necessary re-sampled points to PSC description. In the meantime, it efficiently solves problems of boundary point correspondence, boundary normalization and boundary smoothness. This re-sampling process adopts prior knowledge of body pose structure. Comprehensive experiment is carried out on the CASIA gait database. The proposed method is shown to significantly improve performance of gait recognition under small viewing angle change without additional requirements of supervised learning, known viewing angle and multi-camera system, when compared with other methods in literatures. © 2011 IEEE.
Kusakunniran, W, Wu, Q, Zhang, J & Li, H 1970, 'Speed-invariant gait recognition based on Procrustes Shape Analysis using higher-order shape configuration', 2011 18th IEEE International Conference on Image Processing, 2011 18th IEEE International Conference on Image Processing (ICIP 2011), IEEE, Brussels, Belgium, pp. 545-548.
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Walking speed change is considered a typical challenge hindering reliable human gait recognition. This paper proposes a novel method to extract speed-invariant gait feature based on Procrustes Shape Analysis (PSA). Two major components of PSA, i.e., Procrustes Mean Shape (PMS) and Procrustes Distance (PD), are adopted and adapted specifically for the purpose of speed-invariant gait recognition. One of our major contributions in this work is that, instead of using conventional Centroid Shape Configuration (CSC) which is not suitable to describe individual gait when body shape changes particularly due to change of walking speed, we propose a new descriptor named Higher-order derivative Shape Configuration (HSC) which can generate robust speed-invariant gait feature. From the first order to the higher order, derivative shape configuration contains gait shape information of different levels. Intuitively, the higher order of derivative is able to describe gait with shape change caused by the larger change of walking speed. Encouraging experimental results show that our proposed method is efficient for speed-invariant gait recognition and evidently outperforms other existing methods in the literatures. © 2011 IEEE.
Lai, J, Dutkiewicz, E, Liu, RP & Vesilo, R 1970, 'Joint Admission Control for Cooperative Cognitive Radio Networks', Proceedings of the 6th International ICST Conference on Cognitive Radio Oriented Wireless Networks and Communications, 6th International ICST Conference on Cognitive Radio Oriented Wireless Networks and Communications, IEEE, Osaka, Japan, pp. 276-280.
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This paper studies the performance of admission control in cognitive radio networks (CRNs). We propose a CRN architecture featuring cooperation among several CRNs in the same geographical area. Joint Admission Control (JAC) enables secondary users (SUs) to have access to the combined spectrum pool of the cooperating CRNs. Three joint admission control schemes are investigated and quantitatively analyzed using continuous-time Markov chain analysis. Analytical results reveal new insights that the channel-aware admission control scheme achieves the lowest blocking probability at the expense of communication overhead for obtaining channel usage information in each CRN while the weighted selection scheme obtains the lowest forced termination probability. Moreover, we quantify the gain of cooperation through performance comparison between Joint Admission Control and separate admission control where SUs are restricted to using only one specific CRN. We demonstrate that JAC can achieve significant performance improvement. © 2011 ICST.
Lai, J, Dutkiewicz, E, Liu, RP, Vesilo, R & Fang, G 1970, 'Network selection in cooperative cognitive radio networks', 2011 11th International Symposium on Communications & Information Technologies (ISCIT), 2011 11th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Hangzhou, China, pp. 378-383.
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This paper studies network selection issues in cooperative cognitive radio networks (CRNs) where secondary users (SUs) have access to the combined spectrum pool of cooperating CRNs. Motivated by the service degradation of SUs caused by unnecessary network handover in cooperative CRNs, we formulate the network selection problem as a nonlinear optimization problem to minimize overall SU handover probability. We subsequently propose three network selection schemes and theoretically evaluate their performance using corresponding Markov chain models. Our numerical results indicate that a jointly-optimized network selection scheme which takes into account both the number of free channels and the traffic intensity of primary users in each CRN obtains the lowest probability of SU handover. Furthermore, compared to the random selection scheme, the jointly-optimized network selection scheme achieves significant reduction in SU handover probability while having no negative impact on other performance metrics of secondary users, such as blocking probability, forced termination probability and completion probability. © 2011 IEEE.
Lai, J, Liu, RP, Dutkiewicz, E & Vesilo, R 1970, 'Optimal Channel Reservation in Cooperative Cognitive Radio Networks', 2011 IEEE 73rd Vehicular Technology Conference (VTC Spring), 2011 IEEE Vehicular Technology Conference (VTC 2011-Spring), IEEE, Yokohama, Japan.
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This paper studies optimal channel reservation in cooperative cognitive radio networks (CRNs) where secondary users (SUs) have access to the combined spectrum pool of cooperating CRNs. Motivated by SU high forced termination in cooperative CRNs, we propose two channel reservation schemes, Fixed Channel Placement Reservation (FCPR) and Dynamic Channel Placement Reservation (DCPR), and theoretically analyze their performances using the Markov chain approach. Our numerical results, validated by simulation, indicate that for a given number of reserved channels, the DCPR algorithm achieves better user experience by reducing the forced termination probability. Based on this analysis, we propose two enhanced reservation algorithms: Algorithm A maximizes the overall capacity of CRNs to enable network operators to increase their revenue; Algorithm B minimizes the user experience cost function to provide better services. © 2011 IEEE.
Li, S, Lowe, D, Kong, X & Braun, R 1970, 'Wireless sensor network localization algorithm using dynamic path of mobile beacon', The 17th Asia Pacific Conference on Communications, 2011 IEEE 17th Asia-Pacific Conference on Communications (APCC), IEEE, Kota Kinabalu, Sabah, Malaysia, pp. 344-349.
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Localization is one of the basic prerequisites of sensors in various applications of wireless sensor networks. A beacon is a special sensor with geographical knowledge and which can be employed to help localize general sensors. A mobile beacon is treated as a replacement for many static beacons since it is movable and flexible and often powerful. The path of a mobile beacon will determine the rate of coverage and accuracy of position determination that it supports. Whereas a static path is planned before any localization action, a dynamic path is determined in real-time based on the demands of initially unknown sensors and hence can be more efficient than a static path. In this paper, we proposed a method of localization employed a mobile beacon whose path will be selected according to the real-time information of unknown sensors. The method is designed to be both 'thrifty' in both energy consumption and economical cost, and lightweight in terms of computation load. Simulation results show that the method is lightweight but effective and efficient. © 2011 IEEE.
Li, Z, Wu, Q, Zhang, J & Geers, G 1970, 'SKRWM based descriptor for pedestrian detection in thermal images', 2011 IEEE 13th International Workshop on Multimedia Signal Processing, 2011 IEEE 13th International Workshop on Multimedia Signal Processing (MMSP), IEEE, Hangzhou, China, pp. 1-6.
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Pedestrian detection in a thermal image is a difficult task due to intrinsic challenges:1) low image resolution, 2) thermal noising, 3) polarity changes, 4) lack of color, texture or depth information. To address these challenges, we propose a novel mid-level feature descriptor for pedestrian detection in thermal domain, which combines pixel-level Steering Kernel Regression Weights Matrix (SKRWM) with their corresponding covariances. SKRWM can properly capture the local structure of pixels, while the covariance computation can further provide the correlation of low level feature. This mid-level feature descriptor not only captures the pixel-level data difference and spatial differences of local structure, but also explores the correlations among low-level features. In the case of human detection, the proposed mid-level feature descriptor can discriminatively distinguish pedestrian from complexity. For testing the performance of proposed feature descriptor, a popular classifier framework based on Principal Component Analysis (PCA) and Support Vector Machine (SVM) is also built. Overall, our experimental results show that proposed approach has overcome the problems caused by background subtraction in [1] while attains comparable detection accuracy compared to the state-of-the-arts. © 2011 IEEE.
Liu, RP, Sutton, GJ, Yang, X & Collings, IB 1970, 'Modelling QoS Performance of IEEE 802.11 DCF under Practical Channel Fading Conditions', 2011 IEEE International Conference on Communications (ICC), ICC 2011 - 2011 IEEE International Conference on Communications, IEEE, Kyoto, Japan.
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We consider the impacts of channel fading on the quality of service (QoS) performance of the IEEE 802.11 system. Traditional 2-D Markov chain models, while suitable for throughput analysis, are unable to capture the QoS performance due to the lack of a proper queueing model. We present a 3-D Markov chain queueing model that incorporates channel fading effects and solve the Markov chain efficiently with our Collapsed Transition onto Basis approach. In doing so, we are able to investigate important QoS measures, packet delay and loss, as well as throughput, for a 802.11 system under practical channel fading conditions. The analytical results are validated by extensive simulations. Our 3-D model offers new insights in channel fading effects on system capacity and QoS performance. We demonstrate that our 3-D model can also be used to provides guidelines for traffic control. © 2011 IEEE.
Liu, X & Zhang, J 1970, 'Active learning for human action recognition with Gaussian Processes', 2011 18th IEEE International Conference on Image Processing, 2011 18th IEEE International Conference on Image Processing (ICIP 2011), IEEE, Brussels, Belgium, pp. 3253-3256.
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This paper presents an active learning approach for recognizing human actions in videos based on multiple kernel combined method. We design the classifier based on Multiple Kernel Learning (MKL) through Gaussian Processes (GP) regression. This classifier is then trained in an active learning approach. In each iteration, one optimal sample is selected to be interactively annotated and incorporated into training set. The selection of the sample is based on the heuristic feedback of the GP classifier. To our knowledge, GP regression MKL based active learning methods have not been applied to address the human action recognition yet. We test this approach on standard benchmarks. This approach outperforms the state-of-the-art techniques in accuracy while requires significantly less training samples. © 2011 IEEE.
Moghaddam, Z & Piccardi, M 1970, 'Robust density modelling using the student's t-distribution for human action recognition', 2011 18th IEEE International Conference on Image Processing, 2011 18th IEEE International Conference on Image Processing (ICIP 2011), IEEE, Brussels Belgium, pp. 3261-3264.
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The extraction of human features from videos is often inaccurate and prone to outliers. Such outliers can severely affect density modelling when the Gaussian distribution is used as the model since it is highly sensitive to outliers. The Gaussian distribution is also often used as base component of graphical models for recognising human actions in the videos (hidden Markov model and others) and the presence of outliers can significantly affect the recognition accuracy. In contrast, the Student's t-distribution is more robust to outliers and can be exploited to improve the recognition rate in the presence of abnormal data. In this paper, we present an HMM which uses mixtures of t-distributions as observation probabilities and show how experiments over two well-known datasets (Weizmann, MuHAVi) reported a remarkable improvement in classification accuracy.
Movassaghi, S, Abolhasan, M & Lipman, J 1970, 'Hierarchical Collision-free Addressing Protocol(HCAP) for Body Area Networks', 2011 IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS), IEEE INFOCOM 2011 - IEEE Conference on Computer Communications Workshops, IEEE, Shanghai, China, pp. 543-548.
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In Body Area Networks (BANs) the addressing scheme used to address nodes is fundamental to the effective operation of a BAN. This paper proposes a novel BAN addressing scheme called Hierarchical Collision-free Addressing Protocol (HCAP). Proposed scheme is collision free, reduces power consumption and tackles the address wastage problem. Two important scenarios (random location and fixed location) are defined and studied. Through a series of simulation results we show the efficiency and usability of the proposed scheme in Body Area Networks. © 2011 IEEE.
Movassaghi, S, Abolhasan, M, Lipman, J & IEEE 1970, 'Optimized Prophet Address Allocation (OPAA) for Body Area Networks', 2011 7TH INTERNATIONAL WIRELESS COMMUNICATIONS AND MOBILE COMPUTING CONFERENCE (IWCMC), ACM International Wireless Communications and Mobile Computing Conference, IEEE, Istanbul, Turkey, pp. 2098-2102.
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Each node in a Body Area Network (BAN) needs to be assigned with a free IP address before it may participate in any sort of communication. This paper evaluates the performance of an IP address allocation scheme, namely Prophet allocation to be used for BANs. This allocation scheme is a fully decentralized addressing scheme which is applicable to BANs as it provides low latency, low communication overhead and low complexity. Relative theoretical analysis and simulation experiments have also been conducted to demonstrate its benefits which also represent the reason for the choice of this allocation scheme. It also solves the issues related to network partition and merger efficiently. © 2011 IEEE.
Mudugamuwa, DJ, Wenjing Jia, Xiangjian He & Jie Yang 1970, 'An overcomplete pyramid representation for improved gsm image denoising', 2011 IEEE International Conference on Multimedia and Expo, 2011 IEEE International Conference on Multimedia and Expo (ICME), IEEE, Barcelona, Spain, pp. 1-6.
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Removing noise from a digital image is a challenging problem. Application of Gaussian Scale Mixtures (GSM) in the wavelet domain has been reported to be one of the most effective denoising algorithms, published to date. In this paper we investigate the impact of overcomplete wavelet image representations on the GSM image denoising algorithm. We explore the desirable local characteristics of wavelet coefficients that can enhance the efficiency of GSM denoising and based on the findings, we devise an improved over-complete pyramid representation to enhance the GSM denoising performance. We present the experimental denoising results using the proposed pyramid representation, and they outperform state-of-the-art GSM denoising results reported in the literature. © 2011 IEEE.
Nguyen, DN & Krunz, M 1970, 'A cooperative clustering protocol for energy constrained networks', 2011 8th Annual IEEE Communications Society Conference on Sensor, Mesh and Ad Hoc Communications and Networks, 2011 8th Annual IEEE Communications Society Conference on Sensor, Mesh and Ad Hoc Communications and Networks (SECON), IEEE, Salt Lake City, UT, USA, pp. 574-582.
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Multiple-input multiple-output (MIMO) technology is known to improve energy efficiency in energy-constrained wireless networks, such as wireless sensor networks (WSN). Although in WSNs, a node is often equipped with a single antenna, nodes can be clustered into virtual antenna arrays that can act as virtual MIMO (VMIMO) nodes. In this paper, we propose a distributed cooperative clustering protocol (CCP) that aims at conserving energy and prolonging network lifetime by taking advantage of VMIMO communications. In contrast to previously proposed protocols, CCP fully exploits the diversity gain of the VMIMO technique by optimally selecting the cooperating nodes (CNs) within a cluster and balancing their energy consumption. We first formulate the problem of optimal CN selection at the transmit and receive clusters as a nonlinear binary program, and show the problem is NP-hard. Aiming at minimizing the imbalance in the residual energy at various nodes, we reduce the problem into two sub-problems: finding the optimal number of CNs (ONC) in a cluster and the CN assignment problem. To analytically address the ONC problem, we analyze the energy efficiency of two existing VMIMO methods: distributed Space Time Block Code (DSTBC) and distributed Vertical-Bell Laboratories-Layered-Space-Time (DVBLAST). The second sub-problem is addressed by assigning CNs to nodes with stronger residual energy. To make CCP scalable to large WSNs, we propose a multi-hop energy-balanced routing mechanism for clustered WSNs with a novel cost metric. Our routing method is also applicable to other clustering protocols (e.g., CMIMO, MIMO-LEACH). Extensive simulations are used to validate our analysis. © 2011 IEEE.
Nikodem, J, Klempous, R, Nikodem, M & Chaczko, Z 1970, 'Multi-hop and directed routing based on neighborhood cooperation in WSN', 2011 15th IEEE International Conference on Intelligent Engineering Systems, 2011 15th IEEE International Conference on Intelligent Engineering Systems (INES), IEEE, Poprad, Slovakia, pp. 221-227.
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The paper describes a relational abstraction of neighborhood cooperation for the Wireless Sensor Network (WSN) where node can identify its neighbors around it. Since radio links have limited range only some nodes have a direct contact with the Base Station (BS) and data transmission is executed using multi-hop communication to ensure that information is send from one node to another towards the BS. The novel abstract uses a subordination relation, to manage the neighbor cooperation between the WSN nodes, that exploits topological properties of the WSN. Based on the hop-distance from the BS, any node k is able to establish a set N<(k) consisting of nodes to which k has to send communication messages in order to maintain the data-flow direction towards the BS.
Otoom, AF, Concha, OP & Piccardi, M 1970, 'Boosting mixtures of gaussians under normalized linear transformations for image classification', 7th International Conference on Information Technology and Application, ICITA 2011, International Conference on Information Technology and Applications, IEEE, Sydney Australia, pp. 184-189.
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We address the problem of image classification. Our aim is to improve the performance of MLiT: mixture of Gaussians under Linear transformations, a feature-based classifier proposed in [1] aiming to reduce dimensionality based on a linear transformation which is not restricted to be orthogonal. Boosting might offer an interesting solution by improving the performance of a given base classification algorithm. In this paper, we propose to integrate MLiT within the framework of AdaBoost, which is a widely applied method for boosting. For experimental validation, we have evaluated the proposed method on the four UCI data sets (Vehicle, OpticDigit, WDBC, WPBC) [2] and the author's own. Boosting has proved capable of enhancing the performance of the base classifier on two data sets with improvements of up to 12.8%.
Peng, Y, Xu, M, Jin, JS, Luo, S & Zhao, G 1970, 'Cascade-Based License Plate Localization with Line Segment Features and Haar-Like Features', 2011 Sixth International Conference on Image and Graphics, Graphics (ICIG), IEEE, Hefei, Anchui China, pp. 1023-1028.
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AdaBoost classifiers with Haar-like features are widely used for license plate (LP) localization. However, it normally requires high-dimensional Haar-like features which cause extremely high computational cost. In this paper, a rejection cascade was built for LP localization with reduced Haar-like features. We first introduced line segment features as pre-input of Haarlike features for AdaBoost to eliminate more than 70% of the background in an image. Line segment features, including density, directionality and regularity, were extracted from line segments, which were detected by applying Hough Transform on an edge image. Later, AdaBoost classifiers with Haar-like features were further applied to identify the exact location of license plates. Our method dramatically reduced the demanded dimensions of Haar-like features, therefore saved much time in AdaBoost training stage. By comparing our method with methods of only using Haar-like features and only using line segment features, experimental results demonstrated that our proposed method achieved the best detection rate with significantly reduced dimensions of Haar-like features. © 2011 IEEE.
Pupatwibul, P, Jozi, B & Braun, R 1970, 'Investigating O:MIB-Based Distributed Active Information Model (DAIM) for Autonomics', ICT&A 2011/DEMSET 2011: INTERNATIONAL CONFERENCE ON INFORMATION AND COMMUNICATION TECHNOLOGIES AND APPLICATIONS / INTERNATIONAL CONFERENCE ON DESIGN AND MODELING IN SCIENCE, EDUCATION, AND TECHNOLOGY, Int Conf on Information and Communication Technologies and Applications / Int Conf on Design and Modeling in Science, Education, and Technology, INT INST INFORMATICS & SYSTEMICS, Orlando, FL, pp. 7-12.
Pupatwibul, P, Jozi, B & Braun, RM 1970, 'Investigating O:MIB-based Distributed Active Information Model (DAIM) for Autonomics', International Conference on Information and Communication Technologies ICTA 2011, International Conference on Information and Communication Technologies, International Institute of Informatics and Systematics, Member Int Federation System Research IFSR, Orlando, Florida, USA, pp. 1-6.
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Technological innovations in communication networking, computing applications, and information modeling have played a significant role in managing complex distributed electronic systems. Autonomic Computing (AC) is a concept to deal with the over growing complexity of distributed networks; this term gives systems the ability of self-management, which mean each component in AC can adapt itself to changing conditions of the dynamic environment. In this paper we investigate a new natureinspired Distributed Active Information Model (DAIM) to allow the local decision making process, that will essentially contribute to complex distributed network environments. Details of the DAIM structure are also described, which will hopefully address the schemes of some previous network management protocols such as Simple Network Management Protocol (SNMP), Common Information Model (CIM), and mechanism like Policy-Based Network Management. Finally, we will introduce a benchmark networking system called OpenFlow for applying the DAIM model to enhance autononmic fuctions.
Qin, PY, Guo, YJ & Dutkiewicz, E 1970, 'Capacity enhancement of 2×2 MIMO system using pattern reconfigurable antennas', Asia-Pacific Microwave Conference Proceedings, APMC, Asia-Pacific Microwave Conference, IEEE, Melbourne, VIC, USA, pp. 1694-1697.
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The capacity enhancement of a multiple-input-multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) system using pattern reconfigurable antennas is investigated. In the study, pattern reconfigurable U-slot antennas are incorporated in a 2×2 MIMO-OFDM demonstrator and the channel measurements are conducted in both line-of-sight (LOS) and non-LOS (NLOS) indoor environments. Capacities of the system with pattern reconfigurable and omnidirectional antennas are compared. Measured results show that the pattern reconfigurable antennas can enhance the system capacity, with 17% improvement in the LOS scenario and 12% in the NLOS scenario at a signal-to-noise ratio (SNR) of 10 dB, with respect to the reference omnidirectional antennas. © 2011 Engineers Australia.
Quek, A, Wang, Z, Zhang, J & Feng, D 1970, 'Structural Image Classification with Graph Neural Networks', 2011 International Conference on Digital Image Computing: Techniques and Applications, 2011 International Conference on Digital Image Computing: Techniques and Applications (DICTA), IEEE, Noosa, Queensland, Australia, pp. 416-421.
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Many approaches to image classification tend to transform an image into an unstructured set of numeric feature vectors obtained globally and/or locally, and as a result lose important relational information between regions. In order to encode the geometric relationships between image regions, we propose a variety of structural image representations that are not specialised for any particular image category. Besides the traditional grid-partitioning and global segmentation methods, we investigate the use of local scale-invariant region detectors. Regions are connected based not only upon nearest-neighbour heuristics, but also upon minimum spanning trees and Delaunay triangulation. In order to maintain the topological and spatial relationships between regions, and also to effectively process undirected connections represented as graphs, we utilise the recently-proposed graph neural network model. To the best of our knowledge, this is the first utilisation of the model to process graph structures based on local-sampling techniques, for the task of image classification. Our experimental results demonstrate great potential for further work in this domain. © 2011 IEEE.
Rafiei, A, Abolhasan, M, Franklin, D & Safaei, F 1970, 'Boundary Node Selection Algorithms in WSNs', 2011 IEEE 36TH CONFERENCE ON LOCAL COMPUTER NETWORKS (LCN), IEEE Conference on Local Computer Networks, IEEE, Bonn, Germany, pp. 251-254.
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Physical damage and/or node power exhaustion may lead to coverage holes in WSNs. Coverage holes can be directly detected by certain proximate nodes known as boundary nodes (B-nodes). Due to the sensor nodes' redundant deployment and autonomous fault detection, holes are surrounded by a margin of B-nodes (MB-nodes). If all B-nodes in the margin take part in the hole recovery processes, either by increasing their transmission power or by relocating towards region of interest (ROI), the probability of collision, interference, disconnection, and isolation may increase affecting the rest of the network's performance and QoS. Thus, distributed boundary node selection algorithms (BNS-Algorithms) are proposed to address these issues. BNS-algorithms allow B-nodes to self-select based on available 1-hop information extracted from nodes' simple geometrical and statistical features. Our results show that the performance of the proposed distributed BNS-algorithms approaches that of their centralized counterparts. © 2011 IEEE.
Rahali, E, Chong, WJ, Chaczko, Z & Braun, R 1970, 'Holonic Modelling of Business Process Management', 2011 International Conference on Information Technology Based Higher Education and Training, 2011 International Conference on Information Technology Based Higher Education and Training (ITHET), IEEE, Kusadasi, Izmir, Turkey, pp. 1-6.
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This paper discusses experiences of applying a Holonic approach for Modelling the Business Process Management (BPM) in the telecommunication domain. Topics presented in this paper include shared experiences as well as common problems both experienced and anticipated in adaptation of Holonic approach for specifying and modelling the UMTS technology using the AnyLogic multi-agent based simulation software. The theory of Holonic modelling for BPM would be applied as a development paradigm for the models. © 2011 IEEE.
Sun, Y, Lu, S, Ge, Y, Li, Z & Dutkiewicz, E 1970, 'A power control mechanism for non-cooperative packet forwarding in ad hoc networks', 2011 IEEE 36th Conference on Local Computer Networks, 2011 IEEE 36th Conference on Local Computer Networks (LCN 2011), IEEE, Bonn, Germany, pp. 123-126.
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Based on energy consumption considerations, an ad hoc network node may reject other nodes' forwarding requests to save the limited battery power for its own data transmission. Therefore, a lot of incentive schemes have been proposed to promote the cooperation of the nodes. The utilization of the incentive schemes makes the nodes willing to cooperate with each other, because their non-cooperation can be punished in the future. However, the activities of the nodes in ad hoc networks have some inherent uncertainty. For example, the batteries of some nodes are exhausted or some nodes move to other regions. Under these situations, the existing incentive schemes are no longer effective and the nodes have to terminate their cooperation and stop forwarding packets for others. In this paper, we propose a power control mechanism in ad hoc networks under a dynamic repeated game-theoretic framework. A notion of nodes' evaluation levels for the future experiences is defined to take account of the non-cooperation due to the inherent uncertainty in the ad hoc network nodes' activities. The nodes achieve their optimal transmission efficiency by using a two-step power control mechanism. The simulation results show that compared with the existing schemes our power control mechanism considering non-cooperative packet forwarding improves the average transmission efficiency by approximately 25%. © 2011 IEEE.
Tan, Z, Jamdagni, A, He, X, Nanda, P & Liu, RP 1970, 'Denial-of-Service Attack Detection Based on Multivariate Correlation Analysis', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), International Conference on Neural Information Processing, Springer Berlin Heidelberg, Shanghai, China, pp. 756-765.
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The reliability and availability of network services are being threatened by the growing number of Denial-of-Service (DoS) attacks. Effective mechanisms for DoS attack detection are demanded. Therefore, we propose a multivariate correlation analysis approach to investigate and extract second-order statistics from the observed network traffic records. These second-order statistics extracted by the proposed analysis approach can provide important correlative information hiding among the features. By making use of this hidden information, the detection accuracy can be significantly enhanced. The effectiveness of the proposed multivariate correlation analysis approach is evaluated on the KDD CUP 99 dataset. The evaluation shows encouraging results with average 99.96% detection rate and 2.08% false positive rate. Comparisons also show that our multivariate correlation analysis based detection approach outperforms some other current researches in detecting DoS attacks. © 2011 Springer-Verlag.
Tan, Z, Jamdagni, A, He, X, Nanda, P & Liu, RP 1970, 'Multivariate Correlation Analysis Technique Based on Euclidean Distance Map for Network Traffic Characterization', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), International Conference on Information and Communications Security, Springer Berlin Heidelberg, Beijing, China, pp. 388-398.
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The quality of feature has significant impact on the performance of detection techniques used for Denial-of-Service (DoS) attack. The features that fail to provide accurate characterization for network traffic records make the techniques suffer from low accuracy in detection. Although researches have been conducted and attempted to overcome this problem, there are some constraints in these works. In this paper, we propose a technique based on Euclidean Distance Map (EDM) for optimal feature extraction. The proposed technique runs analysis on original feature space (first-order statistics) and extracts the multivariate correlations between the first-order statistics. The extracted multivariate correlations, namely second-order statistics, preserve significant discriminative information for accurate characterizations of network traffic records, and these multivariate correlations can be the high-quality potential features for DoS attack detection. The effectiveness of the proposed technique is evaluated using KDD CUP 99 dataset and experimental analysis shows encouraging results. © 2011 Springer-Verlag.
Tune, P & Veitch, D 1970, 'Sampling vs sketching: An information theoretic comparison', 2011 Proceedings IEEE INFOCOM, IEEE INFOCOM 2011 - IEEE Conference on Computer Communications, IEEE, Shanghai, China, pp. 2105-2113.
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The main approaches to high speed measurement in routers are traffic sampling, and sketching. However, it is not known which paradigm is inherently better at extracting information from traffic streams. We tackle this problem for the first time using Fisher information as a means of comparison, in the context of flow size distribution measurement. We first provide a side-by-side information theoretic comparison, and then with added resource constraints according to simple models of router implementations. Finally, we evaluate the performance of both methods on actual traffic traces.
Wang, L, He, X, Du, R, Jia, W, Wu, Q & Yeh, W-C 1970, 'Facial Expression Recognition on Hexagonal Structure Using LBP-Based Histogram Variances', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), International Multimedia Modeling Conference, Springer Berlin Heidelberg, Taipei, Taiwan, pp. 35-45.
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In our earlier work, we have proposed an HVF (Histogram Variance Face) approach and proved its effectiveness for facial expression recognition. In this paper, we extend the HVF approach and present a novel approach for facial expression. We take into account the human perspective and understanding of facial expressions. For the first time, we propose to use the Local Binary Pattern (LBP) defined on the hexagonal structure to extract local, dynamic facial features from facial expression images. The dynamic LBP features are used to construct a static image, namely Hexagonal Histogram Variance Face (HHVF), for the video representing a facial expression. We show that the HHVFs representing the same facial expression (e.g., surprise, happy and sadness etc.) are similar no matter if the performers and frame rates are different. Therefore, the proposed facial recognition approach can be utilised for the dynamic expression recognition. We have tested our approach on the well-known Cohn-Kanade AU-Coded Facial Expression database. We have found the improved accuracy of HHVF-based classification compared with the HVF-based approach. © 2011 Springer-Verlag Berlin Heidelberg.
Wang, S, Jia, W, Wu, Q, He, X & Yang, J 1970, 'Learning Global and Local Features for License Plate Detection', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), International Conference on Neural Information Processing, Springer Berlin Heidelberg, Shanghai, China, pp. 547-556.
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This paper proposes an intelligent system that is capable of automatically detecting license plates from static images captured by a digital still camera. A supervised learning approach is used to extract features from license plates, and both global feature and local feature are organized into a cascaded structure. In general, our framework can be divided into two stages. The first stage is constructed by extracting global correlation features and a posterior probability can be estimated to quickly determine the degree of resemblance between the evaluated image region and a license plate. The second stage is constructed by further extracting local dense-SIFT (dSIFT) features for AdaBoost supervised learning approach, and the selected dSIFT features will be used to construct a strong classifier. Using dSIFT as a type of highly distinctive local feature, our algorithm gives high detection rate under various complex conditions. The proposed framework is compared with existing works and promising results are obtained. © 2011 Springer-Verlag.
Wang, S, Wu, Q, He, X & Jia, W 1970, 'More on Weak Feature: Self-correlate Histogram Distances', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), Pacific-Rim Symposium on Image and Video Technology, Springer Berlin Heidelberg, Gwangju, South Korea, pp. 214-223.
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In object detection research, there is a discussion on weak feature and strong feature, feature descriptors, regardless of being considered as 'weak feature descriptors' or 'strong feature descriptors' does not necessarily imply detector performance unless combined with relevant classification algorithms. Since 2001, main stream object detection research projects have been following the Viola Jone's weak feature (Haar-like feature) and AdaBoost classifier approach. Until 2005, when Dalal and Triggs have created the approach of a strong feature (Histogram of Oriented Gradient) and Support Vector Machine (SVM) framework for human detection. This paper proposes an approach to improve the salience of a weak feature descriptor by using intra-feature correlation. Although the intensity histogram distance feature known as Histogram Distance of Haar Regions (HDHR) itself is considered as a weak feature and can only be used to construct a weak learner to learn an AdaBoost classifier. In our paper, we explore the pairwise correlations between each and every histograms constructed and a strong feature can then be formulated. With the newly constructed strong feature based on histogram distances, a SVM classifier can be trained and later used for classification tasks. Promising experimental results have been obtained. © 2011 Springer-Verlag.
Wang, W, Wu, Q, Jia, W & He, S 1970, 'Training-Free License Plate Detection Using Vehicle Symmetry and Simple Features', Proceedings: Twenty-sixth International Conference Image and Vision Computing New Zealand, Image and Vision Computing New Zealand (IVCNZ), Image and Vision Computing New Zealand, Auckland, New Zealand, pp. 260-265.
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In this paper, we propose a training free license plate detection method. We use a challenging benchmark dataset for license plate detection. Unlike many existing approaches, the proposed approach is a training free method, which does not require supervised training procedure and yet can achieve a reasonably good performance. Our motivation comes from the fact that, although license plates are largely variant in color, size, aspect ratio, illumination condition and so on, the rear view of vehicles is mostly symmetric with regard to the vehicles central axis. In addition, license plates for most vehicles are usually located on or close to the vertical axis of the vehicle body along which the vehicle is nearly symmetric. Taking advantage of such prior knowledge, the license plate detection problem is made simpler compared to the conventional scanning window approach which not only requires a large number of scanning window locations, but also requires different parameter settings such as scanning window sizes, aspect ratios and so on.
Xiao, X, Xu, C, Wang, J & Xu, M 1970, 'Landmark recognition and retrieval', Proceedings of the 2011 joint ACM workshop on Human gesture and behavior understanding, MM '11: ACM Multimedia Conference, ACM, Scottsdale, USA, pp. 77-78.
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Existing landmark retrieval methods cannot provide a comprehensive solution, by which user can view different angles of landmark. In this paper, we propose a novel approach to reconstruct and retrieve 3D landmark models by direct 2D to 3D matching. In an offline module, firstly, attention-based 3D reconstruction method is proposed to reconstruct sparse 3D landmark models. Secondly, we construct textured 3D landmark model for each sparse 3D landmark model. Finally, a 3D landmark recognizer is built for each landmark based on the 3D landmark model. In online module, query images are recognized by the 3D landmark recognizers using a 2D to 3D matching approach. For each recognized query image, a 3D landmark model and a 3D landmark texture model are presented as a query result. Experimental results demonstrate the effectiveness of our proposed approach.
Xiaojing Huang & Guo, YJ 1970, 'Wideband AoA Estimation and Beamforming with Hybrid Antenna Array', 2011 IEEE Global Telecommunications Conference - GLOBECOM 2011, 2011 IEEE Global Communications Conference (GLOBECOM 2011), IEEE, Kathmandu, Nepal.
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High speed long range millimetre-wave (mm-wave) links can be achieved by using wideband hybrid antenna arrays of sub-arrays. However, conventional wideband angle-of-arrival (AoA) estimation and beamforming algorithms are not applicable to the wideband hybrid arrays due to the array architecture difference. In this paper, an adaptive frequency-domain AoA estimation and beamforming algorithm suitable for practical wideband hybrid array of side-by-side sub-arrays is proposed. Mean square error bounds under simplified array configuration and extreme array imperfection condition are also given. Simulation results show that the proposed algorithm is robust with low complexity and fast convergence. © 2011 IEEE.
Xu, KC, Guo, YJ, Huang, X & Dutkiewicz, E 1970, 'DoA based positioning employing uniform circular arrays', 2011 11th International Symposium on Communications & Information Technologies (ISCIT), 2011 11th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Hangzhou, China, pp. 328-332.
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In this paper, a methodology of employing a set of uniform circular arrays to localize the 3D position of a target in sensor networks is presented and the theoretical framework is given. Simulation results demonstrate the validity of the method and illustrate the effect of the element pattern on the accuracy of direction of arrival (DoA) estimation and positioning. A weighted least squares method (WLSM) is proposed as a means to increase the robustness of the method. © 2011 IEEE.
Xu, M, Wang, J, Hasan, MA, He, X, Xu, C, Lu, H & Jin, JS 1970, 'Using context saliency for movie shot classification', 2011 18th IEEE International Conference on Image Processing, 2011 18th IEEE International Conference on Image Processing (ICIP 2011), IEEE, Brussels, Belgium, pp. 3653-3656.
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Movie shot classification is vital but challenging task due to various movie genres, different movie shooting techniques and much more shot types than other video domain. Variety of shot types are used in movies in order to attract audiences attention and enhance their watching experience. In this paper, we introduce context saliency to measure visual attention distributed in keyframes for movie shot classification. Different from traditional saliency maps, context saliency map is generated by removing redundancy from contrast saliency and incorporating geometry constrains. Context saliency is later combined with color and texture features to generate feature vectors. Support Vector Machine (SVM) is used to classify keyframes into pre-defined shot classes. Different from the existing works of either performing in a certain movie genre or classifying movie shot into limited directing semantic classes, the proposed method has three unique features: 1) context saliency significantly improves movie shot classification; 2) our method works for all movie genres; 3) our method deals with the most common types of video shots in movies. The experimental results indicate that the proposed method is effective and efficient for movie shot classification. © 2011 IEEE.
Xue, X & Huang, X 1970, 'Block transform OFDM: A robust power and bandwidth efficient system with improved frequency diversity performance', 2011 11th International Symposium on Communications & Information Technologies (ISCIT), 2011 11th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Hangzhou, China, pp. 205-210.
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Block transform orthogonal frequency division multiplexing (BT-OFDM) - a system sitting in-between two extreme data transmission schemes, i.e., the conventional OFDM system and the single-carrier system, with a balanced system performance is proposed in this paper. Through data symbol grouping and block transformation, the BT-OFDM uses reduced size inverse fast Fourier transform to take the advantages of the single-carrier system to overcome the disadvantages of the conventional OFDM system. Frequency domain representation of the BT-OFDM signal reveals that the block transformation implicitly realizes a precoding or block spreading of the transmitted data symbols. When suitable IFFT size is selected, the BT-OFDM also offers the lowest overall system complexity. © 2011 IEEE.
Yang, Y, Cai, Y, Chan, KY, Ramer, R & Guo, YJ 1970, 'MEMS-loaded millimeter wave frequency reconfigurable quasi-Yagi dipole antenna', Asia-Pacific Microwave Conference Proceedings, APMC, Asia-Pacific Microwave Conference, IEEE, Melbourne, VIC, Australia, pp. 1318-1321.
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A new millimeter-wave frequency reconfigurable quasi-Yagi antenna is presented. The quasi-Yagi antenna is printed on a quartz substrate integrated with RF MEMS switches. It consists of one driven dipole, two dipole directors, and one truncated ground plane as reflector. By controlling the actuation of the RF MEMS loaded on the driven and director dipole elements, the antenna operation frequency is switchable in the millimeter wave wireless personal area network (WPAN) band (57-66 GHz) and E-band (71-86 GHz). The end-fire pattern of the Yagi-antenna is maintained in both two-bands. Theoretical results show that the antenna gain varies from 5.5 to 6.7 dBi in the lower band and from 6.5 dBi to 8.1 dBi in the higher band respectively. A high resistive biasing line configuration is presented and its effect on the antenna reflection coefficient is investigated. © 2011 Engineers Australia.
Yang, Y, Karmakar, N & Zhu, X 1970, 'A portable wireless monitoring system for sleep apnoea diagnosis based on active RFID technology', Asia-Pacific Microwave Conference Proceedings, APMC, Asia-Pacific Microwave Conference, IEEE, Melbourne, VIC, USA, pp. 187-190.
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A novel portable wireless monitoring system for sleep apnoea diagnosis is presented in this paper. The presented system is composed of two main parts. The first is an on-body sensor system; the second is a reader and base station. In order to minimize the physical size of the on-body sensors and to avoid interference with 2.4 GHz wireless applications, the system is designed to operate in the 5.8 GHz ISM band. Each on-body sensor system consists of a physiological signal detection circuit, an analogue-to-digital convertor (ADC), a microcontroller (MCU), a transceiver, a channel selection bandpass filter (BPF) and a narrow band antenna. The reader uses 6 narrow band antennas, 6 channel selection BPFs, a transceiver and a MCU. Instead of dealing with channel selection at baseband, multiple passive BPFs at the RF front-end are adopted to select the desired signals, in order to minimize the power consumption and cost of the overall system. Moreover, a 5.8 GHz circular patch antenna is simulated and measured. Both the simulated return loss of 21 dB and the measured one of 26 dB have a 10 dB bandwidth of 140 MHz which satisfies the requirements for the reader system. The measured antenna gain from 5.725 GHz to 5.875 GHz is more than 7.5 dBi. Furthermore, the 3 dB beam-width is about 60° and the front to back ratio is 14 dB. © 2011 Engineers Australia.
Yang, Y, Roy, SM, Zhu, X & Karmakar, NC 1970, 'A novel high selectivity bandpass filter for wireless monitoring of sleep apnoea patients', Asia-Pacific Microwave Conference Proceedings, APMC, Asia-Pacific Microwave Conference, IEEE, Melbourne, Australia, pp. 1590-1593.
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In this paper, a novel high selectivity compact dual planar microstrip bandpass filter (BPF) with compact ring resonator and two uniquely designed defected ground structures (DGSs) is proposed. By employing the inter-digital and spiral DGSs, the filter selectivity can be significantly enhanced with a wide suppression of higher order harmonics. The filter has a selectivity of 220 dB/GHz, passband insertion loss (IL) of 1.55 dB and bandwidth of 61 MHz at 2.53 GHz. Moreover, the proposed compact ring resonator saves 70.5% area compared to a conventional ring resonator. The significance of this BPF to be applied in wireless telemetry monitoring systems has been introduced in this paper. © 2011 Engineers Australia.
Yang, Y, Zhu, X & Karmakar, NC 1970, 'Design of a novel microstrip lowpass filter for UWB chipless RFID readers', Asia-Pacific Microwave Conference Proceedings, APMC, Asia-Pacific Microwave Conference, IEEE, Melbourne, VIC, Australia, pp. 98-101.
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UWB chipless RFID receivers require compact and low cost integration solutions aiming at improving the signal integrity. A wide stopband, high selectivity and compact microstrip lowpass filter (LPF) is therefore needed. A combination of compact microstrip resonant cells (CMRCs) and uniquely shaped defect ground structures (DGS) are used in present LPF design to optimize the filter performances. The stopband with an attenuation level lower than 20 dB is obtained from 3.1 GHz up to 20 GHz. Both simulated and measured results are presented, showing a good agreement between simulation and measurement. © 2011 Engineers Australia.
Yiwei Yu, Dutkiewicz, E, Xiaojing Huang & Mueck, M 1970, 'Inter-Cell Interference Coordination for Type I Relay Networks in LTE Systems', 2011 IEEE Global Telecommunications Conference - GLOBECOM 2011, 2011 IEEE Global Communications Conference (GLOBECOM 2011), IEEE, Kathmandu, Nepal.
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The decode-and-forward relay technique has been introduced in next generation wireless networks (such as LTE) to extend coverage and improve performance, although it may generate additional inter-cell interference. Soft frequency reuse (SFR) has been proposed as the most promising frequency planning strategy to mitigate inter-cell interference in LTE systems. In this paper we propose an effective combination of relay networks and SFR, with a dedicated relay topology and the SFR-based resource allocation scheme. In the proposed relay network, each relay station (RS) can jointly serve cell-edge users from adjacent cells to increase efficiency. The proposed resource allocation scheme, on the other hand, is able to achieve throughput improvement for both cell-edge users and cell-center users by minimizing the interference impact in the system. The benefit of relay networks with SFR-based resource allocation in terms of 30% overall performance improvement over conventional non-relay networks can be realized as demonstrated by the simulation results. © 2011 IEEE.
Yong Cai, Guo, YJ & Peiyuan Qin 1970, 'Frequency switchable quasi-Yagi dipole array for base station antennas', 2011 IEEE International Symposium on Antennas and Propagation (APSURSI), 2011 IEEE Antennas and Propagation Society International Symposium and USNC/URSI National Radio Science Meeting, IEEE, Spokane, WA, USA, pp. 738-741.
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A frequency agile quasi-Yagi dipole sub-array is proposed as an array element for base station antennas. The sub-array consists of four printed Yagi dipole antennas loaded with PIN diodes. The lengths of the director and driven dipole elements can be changed by controlling the PIN diodes states so that the sub-array can operate in either 2.5 or 3.5GHz band. Simulation results show that by using a broadband microstrip-to-coplanar stripline (CPS) feeding structure, the sub-array is well matched with impedance bandwidth (|S11| ≤ 10dB) of 6.5% and 10.5% in the lower and higher bands, respectively. The end-fire fan-beam pattern is obtained across the dual bands, which makes the antenna element suitable for base station applications that require frequency reconfigurability. Predicted gains are 9.4 and 12dBi at 2.5 and 3.5GHz, respectively.
Yu, D, Nanda, P & Braun, R 1970, 'Credibility Problems and Tradeoff between Realistic and Abstraction in WANET and WSN Simulation', 2011 7th International Conference on Wireless Communications, Networking and Mobile Computing, 2011 7th International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM), IEEE, Wuhan, China, pp. 1-4.
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Wireless network Simulation is challenging due to the effect of the dynamic and fading channel. The task is even more challenging in Wireless Sensor Network (WSN), adding the factor of energy source limitation. Validating simulation results with real implementation are still an unresolved question in wireless research in general and in particular WSN. There are few standard procedures to follow which guarantee accuracy and credibility in terms of answering the question in hands. On one hand, simulation results are aimed towards as realistic as possible conforming to real world implementation. On the other hand, abstraction can eliminate the fragmentation of hardware prototypes, operating system models and different simulation tools. In our research we try to tackle credibility problem in WSN with tradeoffs between realistic and abstraction, and setup the principles and guideline for practical simulations in WSN. © 2011 IEEE.
Yu, Y, Dutkiewicz, E, Huang, X & Mueck, M 1970, 'Interference coordination and performance enhancement for shared relay networks in LTE-Advanced systems', 2011 11th International Symposium on Communications & Information Technologies (ISCIT), 2011 11th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Hangzhou, China, pp. 384-389.
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In this paper, we proposed a comprehensive resource allocation scheme to achieve inter-cell interference coordination and performance enhancement for the shared relay network in LTE-Advanced systems. In the scheme, the allocation process is implemented by two steps. The global frequency planning strategies are first employed to realize the interference coordination in the multi-cell environment. Then dedicated local scheduling algorithms are applied to provide further performance enhancement for cell-edge users. As shown in the simulation results, our proposed scheme can achieve the significant performance improvement for cell-edge users while maintaining the high performance for cell-center users, and thus obtain the better performance balance in the system. © 2011 IEEE.
Yu, Y, Dutkiewicz, E, Huang, X & Mueck, M 1970, 'Load Distribution Aware Soft Frequency Reuse for Inter-Cell Interference Mitigation and Throughput Maximization in LTE Networks', 2011 IEEE International Conference on Communications (ICC), ICC 2011 - 2011 IEEE International Conference on Communications, IEEE, Kyoto, Japan.
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This paper proposes a novel load distribution aware soft frequency reuse (LDA-SFR) scheme for inter-cell interference mitigation and performance optimization in next generation wireless networks. Our proposed scheme aims to provide a solution to effectively achieve inter-cell interference mitigation while maintaining high spectrum efficiency to all users in the cell. The proposed scheme consists of two novel algorithms: edge bandwidth reuse and centre bandwidth compensation. Using the edge bandwidth reuse algorithm, cell-edge users can take advantage of uneven traffic load and user distributions within each cell to expand their resource allocations. The center bandwidth compensation algorithm, on the other hand, provides a protection mechanism for cell-center users to avoid exhaustive edge bandwidth extension. Applying LDA-SFR to an LTE network and comparing its performance against that of existing soft frequency reuse (SFR) and adaptive soft frequency reuse (ASFR) schemes indicates that LDA-SFR is superior as it achieves fairness between cell-edge users and cell-center users in terms of average throughput improvement. © 2011 IEEE.
Zhai, H, Jiang, H, Sun, Y, Li, J, Liu, J, Fang, G & Dutkiewicz, E 1970, 'LHCDS: A Novel Deployment Strategy of Proxy Caches for P2P Traffic in ISP Networks', 2011 IEEE 11th International Conference on Computer and Information Technology, 2011 IEEE 11th International Conference on Computer and Information Technology (CIT), IEEE, Pafos, Cyprus, pp. 224-230.
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Peer-to-Peer (P2P) systems have brought two serious problems for Internet Services Providers (ISPs): traffic surges and network congestion. Proxy caching for P2P traffic is an effective means of easing the burden imposed by P2P traffic on ISPs. The deployment strategy of proxy caches has a significant impact on their effect on ISPs. It has two important components: one is cache operation that is what P2P traffic caches monitor and serve; the other is cache deployment algorithm that is where to deploy caches. In this paper, we propose a deployment strategy of proxy caches, called LHCDS (Cache Deployment Strategy for Lower and Higher networks), including a new type of cache operation and its corresponding deployment algorithm. It can serve P2P traffic not only from the local lower access network to the higher transit ISP's network but also within the higher transit ISP's network itself. In LHCDS, caches are deployed at or near core routers of the transit ISP. We develop several deployment algorithms based on the new cache operation. We then evaluate the algorithms, and conclude that the proposed greedy algorithm is a viable and practical algorithm whose performance is close to optimal. Experiments also show that ISPs can achieve more P2P traffic decrease on links using LHCDS than previous strategies. © 2011 IEEE.
Zhang, J, Hanlen, LW, Wang, AY & Xiaojing Huang 1970, 'Superframe-level time-hopping system with variable contention access period for wireless body area communications', 2011 IEEE 22nd International Symposium on Personal, Indoor and Mobile Radio Communications, 2011 IEEE 22nd International Symposium on Personal, Indoor and Mobile Radio Communications - (PIMRC 2011), IEEE, Toronto, Canada, pp. 2178-2182.
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Coexistence of multiple wireless body area networks (WBAN) is a very challenging problem because piconets move frequently and each piconet can have hundreds of sensors. The IEEE 802.15.6 task group is developing a standard based on superframe-level frequency-hopping scheme, which is a good solution to the piconet coexistence problem without requiring coordination between piconets. However, its spectrum efficiency is very low when only a single piconet is operating. In this paper we propose a superframe-level time-hopping scheme with variable contention access period. Compared to the frequency-hopping scheme, the proposed scheme has similar interference mitigation capability, but can achieve significant improvement in energy consumption, latency and spectrum efficiency. © 2011 IEEE.
Zhang, L & Veitch, D 1970, 'Learning Entropy', NETWORKING 2011 Part I, International IFIP-TC Networking Conference, Springer Berlin Heidelberg, Valencia, Spain, pp. 15-27.
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Entropy has been widely used for anomaly detection in various disciplines. One such is in network attack detection, where its role is to detect significant changes in underlying distribution shape due to anomalous behaviour such as attacks. In this paper, we point out that entropy has significant blind spots, which can be made use by adversaries to evade detection. To illustrate the potential pitfalls, we give an in-principle analysis of network attack detection, in which we design a camouflage technique and show analytically that it can perfectly mask attacks from entropy based detector with low costs in terms of the volume of traffic brought in for camouflage. Finally, we illustrate and apply our technique to both synthetic distributions and ones taken from real traffic traces, and show how attacks undermine the detector.
Zhang, L, Veitch, D & Ramamohanarao, K 1970, 'The role of KL divergence in anomaly detection', Proceedings of the ACM SIGMETRICS joint international conference on Measurement and modeling of computer systems, SIGMETRICS '11: ACM SIGMETRICS International Conference on Measurement and Modeling of Computer Systems, ACM, USA, pp. 123-124.
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We study the role of Kullback-Leibler divergence in the framework of anomaly detection, where its abilities as a statistic underlying detection have never been investigated in depth. We give an in-principle analysis of network attack detection, showing explicitly attacks may be masked at minimal cost through 'camouflage'. We illustrate on both synthetic distributions and ones taken from real traffic.
Zheng, C, Dutkiewicz, E, Liu, RP, Vesilo, R, Fang, G & Zhou, Z 1970, 'Opportunistic routing in multi-channel cognitive radio networks', 2011 11th International Symposium on Communications & Information Technologies (ISCIT), 2011 11th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Hangzhou, China, pp. 532-537.
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Cognitive radio (CR) is an exciting technology to improve spectrum utilization. However, spectrum availability can change very fast due to primary user's activity, which makes most of existing CR routing protocols fail to work because they are designed for cognitive radio networks (CRNs) with slow variation of spectrum availability. Opportunistic routing is a promising routing paradigm for CRNs with fast variation of spectrum availability. We propose a multi-channel spectrum aware opportunistic routing (MSAOR) algorithm based on link delay analysis. By introducing channel access probability to characterize the opportunistic CR link, access delay is integrated into queuing delay. Our analysis shows that our algorithm achieves a lower link delay than the existing routing algorithm SAOR (spectrum aware opportunistic routing). Our simulation results also show that our MSAOR algorithm can reduce end-to-end delay by up to 50%, can increase the supported offered load by up to 190% and is more robust than SAOR. © 2011 IEEE.
Zheng, C, Liu, RP, Yang, X, Collings, IB, Zhou, Z & Dutkiewicz, E 1970, 'Maximum Flow-Segment Based Channel Assignment and Routing in Cognitive Radio Networks', 2011 IEEE 73rd Vehicular Technology Conference (VTC Spring), 2011 IEEE Vehicular Technology Conference (VTC 2011-Spring), IEEE, Yokohama, Japan.
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In multi-hop cognitive radio networks (CRNs), there can be dramatic increase in end-to-end delay when a traffic flow switches between a number of channels along its path. We propose a new Maximum Flow-Segment (MFS) based scheme to channel assignment in CRN by minimizing the number of times the channel is switched along a flow. Our MFS based scheme has been efficiently integrated into the AODV on-demand routing protocol. We demonstrate that our MFS based scheme reduces the number of channel switches for the traffic flows and reduces the end-to-end delay by 50%. Our scheme also minimizes the routing overhead, and achieves a higher and more stable throughput than the link based approach. © 2011 IEEE.
